Method of producing glass fibers with metal coatings



March 15, 1960 w rr u s ETAL 2,928,716

METHOD OF PRODUCING GLASS FIBERS WITH METAL COATINGS Filed Nov. 5, 1952 2 Sheets-Sheet 1 INVENTORS:

HAP/W 5. Mv/rE/war a M/zz/A/v H. Orra ATTORNEYQ March 15, 1960 H. B. WHITEHURST ETAL 2,923,716

METHOD OF PRODUCING GLASS FIBERS WITH METAL COATINGS Filed Nov. 5, 1952 2 Sheets-Sheet 2 MoL-rsN GLASS 2 00F GLASS STREAM 2000'! Cal-A55 snzzam- 700F I I I I l I I I I a MOLTEN METAL'700 F If. J

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METAL COATED oLAss' STREAM ROOM TEMPERATURE ATTORNEYS 2 29 f l I I B EE/fi H 8 H .NVE'NTORS- METHOD OF PRODUCING GLASS FIBERS WITH NIETAL COATINGS Harry B. Whitehurst, Granville, and William H. Otto, Newark, Ohio, assignors to Givens-Corning Fiherglas Corporation, a corporation of Delaware Application November 5,1952, Serial No. 318,786

9 Claims. (Cl. 18- 54) This invention relates to glass fibers and particularly to fibers treated to provide strands, yarns, and other textiles having increased abrasion resistance and knot strength. In particular, it relates to coating glass fibers with metals and metal alloys in a way to enhance the properties of the fibers.

It is an object of the invention to apply a metal coating to glass fibers to protect the surfaces and to apply the coating in such a way as to enhance other properties of the fibers.

It is another object of the invention to coat the fibers at temperatures that assure uniform coatings on the fibers and that secure good tensile strength and other properties of the fibers.

In more detail, it is an object to control the temperature of the glass as it is being drawn and as it passes from a molten state to a solidified state with reference to the molten metal to be applied so that the thermal history of the glass fiber is adapted to impart the best properties to the finished product.

In the drawings:

Figure 1 is a schematic side elevational view of apparatus for producing glass fiber strands; I

Figure 2 is a front elevational view of the same apparatus;

Figure 3 is a central longitudinal sectional view on the line 33 of Figure 2 depicting the relationship of parts on a greatly enlarged scale; and

Figure 4 is a front elevational view of a part of the present invention.

Attempts have been made to provide glass fibers with a metal coating which completely surrounds each individual fiber and thereby protects it from adjacent fibers in a strand. The purpose was to increase the abrasion resistance of the fibers to such a point that strands, yarns, and fabrics made from such fibers have greatly increased resistance to abrasion, flexing, knotting, and other Working which in the case of previously produced glass fiber textiles often was destructive. We have found that the properties of the metal-coated glass fibers, especially the uniformity and elfectiveness of coating, the abrasion and flexure resistance, and the tensile strength, were bettered by attention to the thermal experience of the glass strand as it flows from its source, is drawn out into fibers, and is coated with molten metal.

In accordance with the present invention, the molten metal is applied to the fiber or stream immediately after the stream has been drawn out into a fiber and at a point where the stream is at substantially the same temperature as the molten metal being applied to the stream. In this way, the metal coating apparently forms on the glass fiber under ideal conditions. In addition, the thermal experience of the glass fiber itself is apparently adapted to impart to the finished product the best possible properties.

'Metals that may be applied according to the presen invention include most of the common low temperature melting metals, such as Woods alloy, Roses metal, lead,

States Patent 2,928,716 Patented Mar. 15, 1950 alloys of lead and tin, lead and zinc, tin and zinc, brass, bronze, and others. For example, an alloy composed of 99% zinc and 1% titanium may be applied to the fibers at temperatures of about 800 F. Other metals and alloys and their preferable temperatures of application are:

Referring to the drawings, Figure 1 depicts in schematic fashion a fiber producing apparatus which includes a receptacle and feeder 10 for molten glass that may be heated in any conventional manner. The feeder Ill is provided with a series of outlets 12 in its bottom, from which flow a plurality of streams 14 of molten glass. Preferably, the outlets are all arranged in one or two rows so that the streams as they flow from the outlets are all substantially in the same plane. As the streams flow from the outlets 12 they are drawn out into fibers 16 by means of a rotating drum 18 which winds the fibers thereon, and through the winding action exerts a pulling force on the fibers to draw out the streams. Intermediate the source of the streams of molten glass and the wind ing drum 18 a guide shoe 20 is provided with a groove to collect the fibers into a group or strand 22, in which relation the fibers are wound on the drum 18. Various coating and sizing materials may be applied to the fibers as they are being grouped into the strand, for example, a binding material such as starch or synthetic resin may be run onto the shoe to coat the fibers and the strand and secure the fibers together in the strand. The coating or sizing material may also contain a lubricant for the metal-coated fibers, such as petroleum oil, vegetable oil, molybdenum disulfide, wax or other recognized lubricants for metal.

The means for applying molten metal to the fibers as they are being formed includes an applicator 24 which, as shown in Figures 2 and 4, is an elongated receptacle made of graphite and of substantially L shape having a narrow trough 26 extending substantially the full length thereof and enclosed within the vertical extending part of the L-shaped container. The horizontally extending part of the L-shaped container ends in a face 28 which has a plurality of slots 29 therein and through which the fibers 14 pass as they are attenuated on their way to being grouped into a strand. Each one of the slots 29 is connected by means of a small passage 32 with the trough 26 so that molten metal in the trough 26 feeds through the passages to the slots 29. By proper regulation of the level of the molten metal in the trough 26, which can be accomplished by control of the rate of feed of the metal into the trough, sufficient head is maintained on the metal in the passage 32 to force it as a small drop into the slot 29 where, due to its surface tension, it seeks to remain and resist displacement by the glass fiber 14 being drawn through the slot. The glass fiber passing through the slot becomes completely'encased in the drop of metal in the slot so that it is coated with a layer of metal which completely surrounds the fiber and extends uniformly and substantially continuously and uninterruptedly over the fiber surface.

The metal in the applicator is maintained in molten state by heating the applicator by suitable means. For

instance, the body of the applicator may be wound with an electric resistance element 25 which in turn is covered with a layer of insulation 30 such as sillimanite. The

glass temperature are usually suficient. 'there is no reheating of the'stream so that any possible adverse efiect upon the properties of the glass is avoided.

7 3 resistance element is connected across terminals 27 to which-electrical connection is made.

Figure 3 illustrates one example of the present invention employing metals melting at temperatures in the neighborhood of 700 I This view 'shows the -stream 112 of molten glass flowing from the orifice in "the feeder and beingdrawn out into afiber 14. The fiber passes'through the slo t 29 in theend of the applicator 24 and-passes through the glob of molten metal in the slot at the end of the passage 32.

The molten glass is indicated as being at a, temperature of 2200" F .,.which is an approximate average ofthe ;temperatures employed for mostlglasses that are .manu

factured. into, textile fiber form.

.lt is presumed that-shortly after the moltenglass: flows from the orifice-in thegfeeder, the temperature of the aglassdropsto approximately. 2000 F. as shown in Figure 3 and then through the drawing-out or attenuating :range the glass temperaturedrops quickly to avaluecon-.

siderably below that at the feeder outlet. At a distance 'of two or three inches below the end of the opening in the feeder, the stream or fiber will have dropped to about 700 F. If the molten metal is at a temperature of 700 F; then the applicator for the molten metal is located at the point where the streamwould-normally be at 700 so that the stream and the molten metal are at the same temperature.

If desired, the applicator may be at a point where the streamtemperature would be slightly above this point,

say about 725 F., to assure that when the molten metal .is applied to the stream the temperature of the stream will-be substantially 3 equal to'the temperature of the --molten metal but not lower than the molten metal temperature. 'Metal temperatures of 5 F. to 'F. below In this way 'Shortly'after thepoint atwhich the molten metal'is applied to'the stream, the coated stream or fiber falls quickly to room temperature and the fiber together with other similarly coated fibers is wound into a package on the drum 18.

To obtain the metal application to the fibers" while the glass and metal are at the same temperature, the applicator is positioned sufficiently close to the outlet in 'the feeder to assure that the glass will not have timeto cool below the'temperature of the metal. However, if

space requirements limit the approach of the applicator 'to' the feeder, or if the metal being'applied is one that is molten only at such high temperature that it would reqrure thatthe applicator be placed closer to the feeder than is practicable, it may be desirable to incorporate in the glass composition some ingredient which will darken the color ofthe glass and thereby slow down radiation of heatfrom the interior of the glass stream to prolongthe 'time'during which the glass of the stream is athigh temperature to thereby afford a greater space between the feeder and the. applicator.

For instance, copper and other coloring agents may be 'added to'the glass to darken the color of the glass and aid it in retaining its heat for a longer period oftime.-

An example of a glass containing copper and which would operate in this way is as follows:

- vanadium,-or other oxidesordinarily i used in the glass industry for darkening the color of glass, may be added to the glass compositions conventionally used for the manufacture of fibers.

Various modifications maybe made in the invention within the spirit and scope of the appended claims.

'We claim:

1. In the method-of making glass fibers which comprises fiowing a stream of molten glass from a supply thereofiqdrawing out the stream to a fiber and cooling the stream as it is'drawnxout to solidify it in the form of a fiber, the step of forming a coating of metal on the fiberby' applying molten metal to the glass stream at a place along the stream where the. glass of the stream is at a temperature substantially the sauces the temperature of the molten metal immediately prior to its application to the stream.

2.-In the method ofmaking glassfibers which comprises flowing a'stream of molten glass from asupply thereof, drawing out the stream. and cooling the stream as it is drawn out to solidify it in the formof a fiber, the step of forming a coating of metal on the fiber by. passing the stream through a body of molten metal so located solidify it into a fiber, the step of forminga'coating of metal onthe fiber by passing the streamfthrough a body of moltenwmet'al so located along the. stream that the stream as it engages the body of metal is at a temperature 5 to 25 F. above the temperature of the molten metal.

4-. The method of making glass fibers which comprises continuously flowing streams of molten glass from a supply thereof, continuously drawing out the streamsand cooling the streams as they are drawnout toflsolidify themin the form of fibers, forming coatings of metal on at least some of the individual fibers by passing at least some of the streams through bodies of molten metal so located along the. stream that the streamsas they engage the bodies of metal are at atemperature substantially the same as the temperature of the molten metal, and solidifying on the fibers the metal so applied.

5. The method of making glass fibers which comprises ,continuouslytflowing streams of molten glass from a supply thereof, continuously-drawing out the streams and cooling the streams as they aredrawn out-to solidify themin the form .of fibers, continuously collecting the drawnaout streams into a strand, forming-a coating-of metal on the individual fibers'by applying to the streams beforethey. are collected into the strand: a molten metal that .isl-applied to the streams at such a placealong the streams thatthetemperature of: the glass is substantially the same as thetemperature of the molten metal prior to its application, and solidifyingon the fiber surfaces the metal soapplied.

- 6. The method ofmaking glassfibers which comprises flowing streams of molten glass from-asupply thereof,

along the streams wherethe temperature of the glass is 'substantially the'same as the'ternperatureof the metal {prior to its application, solidifyingthe metal coating, and

applying a second coating material to thestreams as they are collected intothe group. v

7. The method of making glassfibers which comprises flowing a stream of molten-glass from a supply thereof, ='dra-wing-"out thestream and'cooling the stream-as 'itis drawn out to solidify it in the form of a fiber, and passing the stream through a body of molten metal located at a point where the glass of the stream is at a temperature 5 to 25 F. above the temperature of the molten metal prior to its application.

8. The method of making glass fibers which comprises continuously flowing streams of molten glass from a supply thereof, continuously drawing out the streams and cooling the streams as they are drawn out to solidify them in the form of fibers. Continuously collecting the drawn-out streams into a group to form a strand, and applying to the streams before they are collected into the group a molten metal that is applied at a place where the temperature-of the glass of the stream is 5 to 25 F. above the temperature of the molten metal prior to its application.

9. The method of making glass fibers which comprises continuously flowing streams of molten glass from a supply thereof, continuously drawing out the streams and 1 cooling the streams as they are drawn out to solidify them in the form of fibers, continuously collecting the drawn- References Cited in the file of this patent UNITED STATES PATENTS 2,053,923, Stewart Sept. 8, 1936 2,224,149 'Fisher Dec. 10, 1940 2,272,588 Simison Feb.. 10, 1942 2,373,078 Kleist Apr. 3, 1945 2,616,165 Brennan Nov. 4, 1952 FOREIGN PATENTS 840,209 France Ian. 11, 1939 

1. IN THE METHOD OF MAKING GLASS FIBERS WHICH COMPRISES, FLOWING A STREAM OF MOLTEN GLASS FROM A SUPPLY THEREOF, DRAWING OUT THE STREAM TO A FIBER AND COOLING THE STREAM AS IT IS DRAWN OUT TO SOLIDIFY IT IN THE FORM OF A FIBER, THE STEP OF FORMING A COATING OF METAL ON THE FIBER BY APPLYING MOLTEN METAL TO THE GLASS STREAM AT A PLACE ALONG THE STREAM WHERE THE GLASS OF THE STREAM IS AT A TEMPERATURE SUBSTANTIALLY THE SAME AS THE TEMPERATURE OF MOLTEM METAL IMMEDIATELY PRIOR TO ITS APPLICATION TO THE STREAM. 